java.lang.String.indexOf()用法

import java.lang.*;

public class StringDemo {

public static void main(String[] args) {

String str = "This is tanglc's cnblog";

// returns the index of character s appear in the first time
System.out.println("index of letter 's' = "
+ str.indexOf('s'));

// returns -1 as character e is not in the string
System.out.println("index of letter 'e' = "
+ str.indexOf('e'));
}
}

index of letter 's' = 3
index of letter 'e' = -1